1. Field of the Invention
The present invention relates to an automotive safety device which, upon the onset of a collision, deploys an inflatable restraint cushion, commonly known as an air bag, so as to provide impact protection to occupants of the passenger vehicles. More particularly, this invention relates to a device for securing an inflator having a constant cross section to a passenger side air bag canister.
2. Description of Related Art
An air bag restraint system, referred to as a module, typically includes a canister which encloses a gas generator or, as it is commonly known, an inflator, and at least part of an air bag cushion, and a cover which conceals the module from view. When the vehicle is involved in a collision, a crash signal initiates operation of the inflator to cause the air bag cushion to deploy. The inflator produces an inert gas (e.g., nitrogen) which is directed under pressure into the air bag cushion to force it out of the canister incorporated into the module and into the passenger compartment of the vehicle. In a pyrotechnic-type inflator, gas is produced by the burning of a gas generating material. As the air bag cushion is forced out of the container, pressure exerted on the cover causes selected portions of the cover to separate in a predetermined manner along tear seams to enable the air bag cushion to be directed into the passenger compartment. As the air bag cushion is directed into the passenger compartment, it is inflated by the continued flow of gas produced by the inflator. One possible location for an air bag assembly is in the instrument panel or dashboard on the passenger side of the vehicle.
A standard pyrotechnic inflator 10 is shown in FIG. 1. The inflator 10 has an elongated tubular structure 12 with an open end 14 which is sealed with an end cap 16 having a flange 18, and a closed end 20 having an integral mounting stud 22 for attaching the inflator 10 to a canister 24. The overall length of the inflator 10 is greater than the length of the canister 24. The pyrotechnic inflator 10 is installed in the canister 24 by passing the inflator 10 through an opening 26 in the first side wall 28 and inserting the mounting stud 22 through an aperture 30 formed in the second side wall 32 of the canister 24 and securing the mounting stud 22 with a nut 34. The flange 18 is thereby engaged with the opening 26 to secure both ends of the inflator 10. As passenger side inflator designs are modified to provide better performance at a reduced cost, the outward appearance and the procedure for installing the inflator may be changed. In one design, the mounting flange 18 is eliminated to form an inflator 10 having a substantially constant diameter to improve performance and the structural integrity of the inflator 10. With this modification, attachment of the passenger side inflator to conventional air bag canisters may not be possible.
A possible solution is shown by Good, U.S. Pat. No. 5,069,480, wherein a recessed boss is provided for accepting the sealed end of an inflator. This design requires modification of the canister end panel thus requiring substantial retooling. Further, the recessed boss must be sized for one specific inflator diameter, thereby causing extensive changes should the inflator diameter be changed.
A second possible solution is shown in Jarboe et al., U.S. Pat. No. 5,197,756, wherein a sleeve having diametrically opposed flanges that extend outwardly of the sleeve is attached to a tongue formed into the air bag canister. The sleeve is connected to the inflator housing by press fit, shrink fit, or tongue-and-groove techniques. This design requires a specifically designed air bag canister. Further, the sleeve must be sized for each inflator.